I'm possibly gonna buy a set of AFR heads soon for my 350 TBI. What kind of gains can i get from these? Also, if i got the 68cc chambers, how much would that raise my compression? will the computer be able to compensate for that?

thanks
nate

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1991 Chevrolet S10, 350 TBI/ TH350

 

HUGE gains. 68cc would lower your compression I think. You probably have 64cc. What 350 do you have?
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-Tas
'89 Formula WS-6 made in Van Nuys, CA, U.S.A.

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EFI & Intake Options

[This message has been edited by Tas (edited December 09, 2001).]

 

I have a 350 TBI from a 91 Suburban. What do you mean by HUGE gains? How much horsepower?

thanks
nate

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1991 Chevrolet S10, 350 TBI/ TH350

 

you have an L05. With a single plane intake and a cam you could get 100HP easy

 

Not a chance. Better count on getting the prom burning stuff.

 

i don't know if you have your heart set on the afr's, but in several side by side comparisons i have seen both gm fast burn heads and trick flow twisted wedge heads made more power. i think the afr's had a higher peak power, and gm and trick flow had a better average hp and a flatter torque curve.

later
tim

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91 Camaro RS-LO3,Auto
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I would think with an LT1 cam you could easily pull mid 300hp range with AFR heads. You will need a chip to get full use of your combo but a little playing with base timing and fuel pressure will get you up and running.

 

Since he has a L05, wouldn't an LT1 cam be mild with AFR or Fast burn heads? I think LT4 cam plus 1.6 RR's is more of the ticket... I could be wrong though.



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1991 Firebird Bandit II Edition
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There isn't a whole lot of difference in the LT1 vs. LT4 cams especially given you have to buy 1.6 ratio rockers. LT1 cams are nice and TBI friendly. I love it in my L05 with ported stock heads in my truck. I am running stock chip with 6 degrees base timing and 15psi fuel pressure. It runs a little fat at idle but screams to 5500rpm. A major improvement over stock. I haven't got around to burning a chip for it.

 

I have TFS 23 degree heads on my 84 Xfire. I swear by them. The AFR's are a great cylinder head, but bang for the buck, the TFS is hard to beat.

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What about the edelbrock heads? are they any good? i want the most performance i can get for this motor.

nate

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1991 Chevrolet S10, 350 TBI/ TH350

 

i have edelbrock heads on my car. they are very good i must say, i choose them because of the 60cc chamber, and the fact that the fast burns were not yet released for sale when i was ready to buy my loss on that one i guess.
but for a 350 i would prolly go with tfs or fast burns. both make huge power and cost about the same as the edelbrocks. i think the fast burns are actually the cheapest ones at around 900bucks, the edelbrocks and tfs's are both right around 1000.

later
tim



------------------
91 Camaro RS-LO3,Auto
New Times Coming Soon!
Check Out The East Coast F-Body Nationals Home Page
www.geocities.com/njspeeder
My MAFB.ORG Home Page
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DSI Racing Home Page
www.geocities.com/foff667

 

NJSpeeder-

Will those Fast Burn heads work with my Edelbrock Performer Intake, and all my emmsisons stuff?

thanks
nate

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1991 Chevrolet S10, 350 TBI/ TH350

 

NOPE Fastburns are Vortec designed. requiring Vortec intake and EGR ports.

 

FastBurn heads are now $1100 for a set and the Vortec intakes don't even 100% line-up with their intake ports and the exhaust ports are not "centered" around the header bolts.

Easy 400hp with just a ZZ4 cam (only 208/221 duration at .050"!!!), 1.6/1.5 full roller rockers, RPM intake and nice 1-5/8" exhaust. Well, with a carb, anyway. 9.5:1 CR minimum needed, IMO, for that cam to be efficient in a daily driver...

 

Can't u just plug the egr holes on the Fast Burns... Are the Fast Burn heads also known as Vortec Aluminum heads? Who makes a Vortec intake that will work on a TBI engine?

-Timbo-

 

Vortec and FastBurn heads do not have exhaust crossover passages/holes, or the "EGR" holes you speak of. The EGR gasses are plumbed into the intake manifold and are pirated from an exhaust header tube. (instead of coming from the exhaust crossover passages, which don't exist)

Also, Fastburn head exhaust ports are about .2" above the normal, OEM, centered versions. Really need custom headers for FastBurns.

 

I got my new AFR catalog and I can get the bare heads for $740 and the full dressers are $1250. $500 seems like a lot of $$ for the accessories.

 

You got expensive valves ($10-15 each THEIR cost), expensive springs, expensive seals, labor for guide height check, expensive/light/strong caps, expensive/strong locks, first-time assembly labor, then installed-height check labor and shim cost/installation labor, finish valve lapping labor, casting/flash removal and touch-up labor, labor I have forgotten and the final flow test labor.

 

brharris, How much porting did you do to your stock heads? They were the swirl ports, right? Do you think the cam or heads made more of a difference? I have a mostly stock LO5 that I would like to make pull better in the upper RPMs for not to much money, while I save up for a 383. It sounds like you really like your combo and it could be done for cheap!!